The demonstrated importance of enzymes in body fluids suggests that a further knowledge of the enzymatic composition of the aqueous humor may eventually be clinically useful.1 Studies of enzymes have been reported for the retina, lens, cornea, and vitreous, but aside from studies of electrolyte composition, little interest has been devoted to such investigations of the aqueous humor.2 The low protein content of primary aqueous has discouraged previous investigation of its enzyme activity, and only fragmentary reports have been made indicating low or absent activity of cholinesterase, hyaluronidase, and lysozyme.3-6 Conventional methods of investigation are of limited usefulness in the study of aqueous, because more than 0.15 ml. is seldom available for study, and present evidence indicates its enzyme content to be very low. With sensitive microchemical techniques, however, further biochemical studies are possible despite these limitations.7,8 In this study newer techniques of quantitative microchemistry were